163
Troubleshooting
Alarm
Code
43
Activation of Low Compression Ratio Protection Device
● The RUN indicator (Red) is ashing
● The indoor unit number, the alarm code, the unit model code and the connected number of indoor units are displayed on
LCD. Meanwhile, the indoor unit number and the alarm code are displayed on the 7-segment of outdoor unit PCB.
★
This alarm code is indicated when the following condition occurs more than twice in 30 minutes. A compression ratio
ε = {(Pd + 0.1) / (Ps + 0.06)}, calculated from a discharge pressure (Pd MPa) and suction pressure (Ps MPa) is lower
than 1.8 for 2 minutes.
Does the inverter operate?
Yes
Does the compressor operate?
Is the reversing valve spindle
mounted at middle position?
Are the high-pressure sensor and
the low-pressure sensor normal?
Yes
Check that the indoor/outdoor intake
air temperature is not too low.
Replace the high-pressure sensor
or the low-pressure sensor if faulty.
Check the compressor and
power cable.
Check the inverter.
Replace the reversing valve if faulty.
No
No
No
No
Is there a leak in the Solenoid
Valve for Hot Gas Bypass (SVA)?
Yes
No
Yes
Replace the Solenoid Valve
(SVA) if faulty.
Yes
Cause Check Item
Action
(Turn OFF Main Switch)
Phenomenon
Excessively
Low Compression
Ratio
Check compressor. Replace comp. if faulty.
Compressor is not Operating
Check inverter. Repair faulty part.Inverter is not Functioning
Measure suction pipe
temp. of reversing valve.
Replace reversing valve
if faulty.
Valve Stoppage at Middle
Position of Reversing Valve
Check connector for
O.U. PCB, power supply
and pressure indication.
Replace sensor if faulty.
Abnormality of High or Low
Pressure Sensor
Check indoor unit and
outdoor unit air temp.
thermistor.
Replace thermistor
if faulty.
Excessively Low Indoor
Intake Air Temperature
Check Solenoid Valve.
Replace SVA if leakage
occurs.
Leakage from Solenoid
Valve (SVA)
O.U. PCB: Outdoor Unit PCB
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